Threaded plastic closures formed from suitable polymeric materials have met with widespread acceptance in the market place for use on bottles and like containers, including those for carbonated and non-carbonated beverages. Efficient and versatile use of such closures is facilitated through the use of high-speed, automated capping equipment, which equipment is configured to rotatably apply each closure to an associated container so that an internal thread formation of the closure threadingly engages and mates with an external thread formation provided on the neck portion of the associated container.
In order to grip each closure as it is applied to an associated container, automated capping equipment of this type typically includes a plurality of rotatably driven capping chucks or heads. Each capping chuck is configured to releasable retain and grip a closure as the closure and an associated filled container are positioned for application of the closure. In a typical arrangement, the capping chuck is rotatably driven, together with the closure retained therein, relative to the associated container so that threaded application of the closure to that container is effected. Capping chucks of this nature are typically provided with a torque-limiting mechanism, whereby the closures are applied to the desired tightness on the associated container, and rotational drive of the capping chuck and closure discontinued. The capping chuck is thereafter disengaged from the closure, and the filled container and closure package is moved from the capping machine.
Versatile operation of this type of automated capping equipment is facilitated by configuring each capping chuck to accommodate application of differently sized closures. To this end, some capping chucks are provided with moveable, jaw-like elements which can “float” or shift to accommodate application of closures of different sizes. However, depending upon the specific configuration of such capping chucks, the closure may not necessarily be held in centered, coaxial relationship with the associated container. Eccentric contact between the bottom of the closure and the top of the associated container finish can undesirably result in improper positioning of the closure in the capping chuck, leading to an application defect such as a cocked or cross-threaded closure.
The present invention is directed to an improved capping chuck assembly which facilitates application of differently sized closures, having differing exterior features, while avoiding undesirable misapplication of the closures to associated containers.